Musical notes are classified by frequency. The note middle C has a frequency of 262 hertz. The note C above middle C has a frequency of 524 hertz. The note C below middle C has a frequency of 131 hertz.
a. Write an equation of the sine function that represents middle C if its amplitude is 0.2.
b. Write an equation of the sine function that represents C above middle C if its amplitude is one half that of middle C.
c. Write an equation of the sine function that represents C below middle C if its amplitude is twice that of middle C.